I am using the Weatherlink serial data logger. Does the datalogger's data need to be cleared occasionally or will the new data overwrite the old?

I believe the buffer in the datalogger itself overwrites itself continually; however, the data stored in the WeatherLink directory of your hard drive (if you are using WL), continues to accrue until it is moved, stored, or you run out of space

(From the manual)=================You may have the software automatically clear the archive memory whenever it downloads data. Clearing after each download will decrease the time it takes to download because there will be less “accumulated” data in the archive memory. Not clearing after each download allows you to download data into multiple databases (if more than one person uses asingle weather station, for example). To clear data in the archive memoryafter each download, select the check box.=================

Also of possible interest:(From the manual)=================The archive memory is the weather information storage area in the WeatherLink itself. At each archive interval the WeatherLink stores one record to archive memory. The WeatherLink has room in the archive memory for approximately 1 day of weather data for each minute in the archive interval. For example, if you use the 1 minute archive interval, the WeatherLink may store approximately 1 day of data.

If you use the 30 minute archive interval, the WeatherLink may store approximately 30 days of data. If you use the 2 hour archive interval (120 minutes), the WeatherLink may store approximately 120 days of data.=================If you use 1 minute intervals, and you lose power to your computer for more than a day, you will lose data... I used to use 1 minute intervals, now I have it set to 5 minutes. There's a thread somewhere on this issue...

Data is not erased from the archive when you download. The Vantage Proand Vantage Pro2 consoles are smart enough to send only the dataaccumulated since the last time you downloaded. The data remains in thedata logger as a backup until you intentionally clear the memory, resetthe archive interval, or the archive memory is full.

Since this backup data is stored on the logger, you can restore editsyou have made near the end (the more recent data) of the database.Delete the last records from the database file and download again. Ifyou want to see how many records are stored in the archive memory,download into an empty database. The entire archive is downloaded.